Fiber based RF phased-array antennas

Abstract

Described is a flexible thermally-drawn receive phased array antenna and antenna system and a process for making the same. The phased array antenna system includes a plurality of antenna elements and one or more low noise amplifiers (LNAs) encapsulated in a fiber such as flexible polyetherimide (PEI) fiber material. A DC bias for the LNAs and other components is provided by one or more electrically conducting wires disposed in proximity to the antenna elements and also encapsulated in the fiber. In embodiments, the antenna elements are provided as dipole antenna elements and the phased array antenna is provided as a flexible thermally-drawn linear dipole receive phased array antenna operable at UHF frequencies.

What is claimed is: 
     
       1. A photonics/radio frequency (RF) array antenna system comprising:
 a plurality of dipole antenna elements; 
 one or more optical input signal paths coupled to the plurality of RF/optical modules; 
 one or more optical output signal paths coupled to the plurality of RF/optical modules; 
 a plurality of RF/optical modules coupled to respective ones of the plurality of dipole antenna elements, and coupled to at least one of the one or more optical input signal paths and at least one of the one or more optical output signal paths, the RF/optical modules configured to process RF signals provided thereto from the respective one of the plurality of dipole antenna elements and provide optical signals at one or more outputs thereof; and 
 a fiber material encapsulating the plurality of dipole antenna elements, the plurality of RF/optical modules, the one or more optical input signal paths and the one or more optical output signal paths. 
 
     
     
       2. The photonics/RF array antenna system of  claim 1  further comprising at least one power bus coupled to the plurality of RF/optical modules. 
     
     
       3. The photonics/RF array antenna system of  claim 2  wherein the plurality of dipole antenna elements are arranged in the fiber material as a linear array of dipole antenna elements. 
     
     
       4. The photonics/RF array antenna system of  claim 3  further comprising a plurality of offset RF feed circuits, each of the plurality of offset RF feed circuits coupled to a corresponding one of the plurality of dipole antenna elements at a point which is offset from a center point of the dipole antenna element to which the offset RF feed circuit is coupled. 
     
     
       5. The photonics/RF array antenna system of  claim 4  wherein an amount of offset of the offset RF feed circuit is selected based upon a characteristic of the at least one power bus. 
     
     
       6. The photonics/RF array antenna system of  claim 5  wherein an amount of offset of the offset RF feed circuit is selected based upon a distance of the at least one power bus to a dipole antenna element. 
     
     
       7. The photonics/RF array antenna system of  claim 5  wherein the at least one power bus comprises a pair of electrically conducting wires and an amount of offset of the offset RF feed circuit is selected based upon one or more characteristics of the pair of electrically conducting wires. 
     
     
       8. The array antenna system of  claim 1  wherein:
 the fiber material is a flexible polyetherimide (PEI) fiber material; and 
 the plurality of dipole antenna elements are encapsulated in the flexible PEI fiber material. 
 
     
     
       9. The array antenna system of  claim 1  wherein the RF/optical modules comprise:
 means for coupling RF signals from each fiber encapsulated antenna elements to a respective one of the RF/optical modules to; 
 one or more RF amplifiers configured to receive RF signals from a corresponding one of the fiber encapsulated antenna elements; and 
 one or more RF-to-optical converters, coupled to receive an RF signal provided to a first input port thereof, an optical signal provided to a second input port thereof and to provide a corresponding optical signal at an output port thereof. 
 
     
     
       10. A flexible thermally-drawn dipole receive phased array antenna comprising:
 a plurality of dipole antenna elements; 
 one or more low noise amplifiers (LNAs), each of the one or more LNAs configured to receive signals from one or more of the plurality of dipole antenna elements; 
 a pair of electrically conducting wires disposed proximate at least some of the plurality of dipole antenna elements wherein the pair of electrically conducting wires are configured to couple one or more DC bias signals to the one or more LNAs; 
 a like plurality of offset feed circuits, each offset feed circuit coupled to a corresponding one the plurality of dipole antenna elements at a point which is offset from a center point of the dipole antenna elements wherein an amount of the offset is selected to provide a selected impedance match between the plurality of dipole antenna elements and corresponding ones of the one or more low noise amplifiers (LNAs) to which the dipole antenna elements are coupled; and 
 a fiber material encapsulating the plurality of dipole antenna elements and the one or more LNAs. 
 
     
     
       11. The flexible thermally-drawn dipole receive phased array antenna of  claim 10  wherein an amount by which each offset feed circuit is offset from the center point of the dipole antenna element to which it is coupled is selected based upon a location of the pair of electrically conducting wires. 
     
     
       12. The flexible thermally-drawn dipole receive phased array antenna of  claim 10  wherein the one or more LNAs correspond to a plurality of LNAs, each of the plurality of LNAs configured to receive signals from one or more of the plurality of dipole antenna elements. 
     
     
       13. The flexible thermally-drawn dipole receive phased array antenna of  claim 10  wherein the one or more LNAs correspond to a plurality of LNAs, each of the plurality of LNAs configured to receive signals from a corresponding one of the plurality of dipole antenna elements. 
     
     
       14. The flexible thermally-drawn dipole receive phased array antenna of  claim 10  wherein the plurality of dipole antenna elements are arranged as a linear array of dipole antenna elements. 
     
     
       15. The flexible thermally-drawn dipole receive phased array antenna of  claim 10  further comprising a plurality of radio frequency (RF)/optical modules, each of the plurality of RF/optical modules coupled to a corresponding one of the plurality of dipole antenna elements wherein the fiber material encapsulates the plurality of RF/optical modules. 
     
     
       16. A phased array system comprising:
 a plurality of dipole antenna elements; 
 a plurality of radio frequency (RF)/optical modules, each of the plurality of RF/optical modules coupled to a corresponding one of the plurality of dipole antenna elements; 
 one or more optical input signal paths coupled to the plurality of RF/optical modules; 
 one or more optical output signal paths coupled to the plurality of RF/optical modules; and 
 one or more electrically conducting wires disposed to couple one or more DC bias signals to the plurality of RF/optical modules; and 
 a fiber material encapsulating the plurality of dipole antenna elements, the plurality of RF/optical modules, the one or more electrically conducting wires, the one or more optical input signal paths and the one or more optical output signal paths. 
 
     
     
       17. The phased array system of  claim 16  wherein the one or more electrically conducting wires are disposed in proximity to at least some of the plurality of dipole antenna elements. 
     
     
       18. The phased array system of  claim 16  further comprising a plurality of offset feed circuits, selected to provide an input impedance match between the dipole antenna element and the RF/optical module to which the dipole antenna element is coupled. 
     
     
       19. The phased array system of  claim 18  wherein an amount of offset of each of the respective ones of the plurality of offset feed circuits is selected based upon a distance of the one or more electrically conducting wires to the respective ones of the plurality of dipole antenna elements. 
     
     
       20. The phased array system of  claim 19  wherein the plurality of RF/optical modules comprise:
 one or more RF amplifiers configured to receive RF signals from a corresponding one of the plurality of fiber encapsulated dipole antenna elements; and 
 one or more RF-to-optical converters, coupled to receive an RF signal provided to a first input port thereof, an optical signal provided to a second input port thereof and to provide a corresponding modulated optical signal at an output port thereof.